MPL 20x3x2 / N38 - lamellar magnet

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their consistent magnetism, neodymium magnets have these key benefits:

• They have unchanged lifting capacity, and over around 10 years their performance decreases symbolically – ~1% (in testing),
• They protect against demagnetization induced by external magnetic fields effectively,
• By applying a shiny layer of gold, the element gains a clean look,
• They exhibit extremely high levels of magnetic induction near the outer area of the magnet,
• Thanks to their enhanced temperature resistance, they can operate (depending on the form) even at temperatures up to 230°C or more,
• With the option for tailored forming and precise design, these magnets can be produced in various shapes and sizes, greatly improving design adaptation,
• Significant impact in cutting-edge sectors – they find application in data storage devices, electric motors, healthcare devices as well as other advanced devices,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are fragile when subjected to a powerful impact. If the magnets are exposed to shocks, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from fracture and additionally reinforces its overall strength,
• They lose power at extreme temperatures. Most neodymium magnets experience permanent degradation in strength when heated above 80°C (depending on the shape and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Magnets exposed to humidity can oxidize. Therefore, for outdoor applications, we advise waterproof types made of non-metallic composites,
• Limited ability to create precision features in the magnet – the use of a magnetic holder is recommended,
• Safety concern due to small fragments may arise, especially if swallowed, which is significant in the protection of children. Furthermore, minuscule fragments from these devices may complicate medical imaging when ingested,
• Due to expensive raw materials, their cost is considerably higher,

Magnetic strength at its maximum – what affects it?

The given strength of the magnet means the optimal strength, assessed in the best circumstances, specifically:

• with mild steel, serving as a magnetic flux conductor
• of a thickness of at least 10 mm
• with a refined outer layer
• with zero air gap
• with vertical force applied
• in normal thermal conditions

Practical lifting capacity: influencing factors

In practice, the holding capacity of a magnet is affected by the following aspects, from crucial to less important:

• Air gap between the magnet and the plate, because even a very small distance (e.g. 0.5 mm) can cause a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

* Lifting capacity testing was conducted on plates with a smooth surface of optimal thickness, under perpendicular forces, however under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a small distance {between} the magnet and the plate lowers the lifting capacity.